Tsuyoshi Ogura

Parallelization of IP-packet filter rules

A compiler for parallelizing IP-packet filter rules is presented which will improve network security and reduce packet-forwarding performance degradation. It analyzes the interdependence of packet-filtering rules specified by a network administrator and translates them into an intermediate program whose instructions can be executed in parallel. Three types of compiler operations are introduced: division is used to divide the rules into parallel expressions, simplification is used to simplify redundant rules, deletion is used to delete infeasible rules.

Real-time processing method for an ultra high-speed streaming server running PC Linux

Integration of a high-resolution video (such as HDTV) delivery system for IP networks with legacy DBMSs and WWW systems, would make it easy to achieve system for a remote video editing, remote education and digital cinema. For this reason, we have developed a streaming server for IP networks is based on the MAPOS link-layer protocol and has a 2.48-Gbps line speed. The MAPOS protocol enables IP networks over SONET/SDH. The streaming server is constructed on a typical PC with Linux. Choosing a PC and Linux provides high performance at low cost to users. Real-time processing is important if we are to send video data at a specified rate. To implement a streaming server that can deliver Gbps video streams, we developed a real-time processing method specifically for this platform. Consequently, we obtained real-time performance for a streaming server in which the method was implemented. To evaluate its performance, we measured the receiving rate and jitter on receiving terminal while the server was delivering video streams at rates from 1.5 to 2.4 Gbps. The jitter indicates the receive-buffer size that is required and the initial delay which should be inserted before playback. For video delivery at 1.5 Gbps, the maximum buffer size was shown to be 936 KBytes (5.1 msec) and initial delay was 3.0 msec. These results show the practicability of constructing a system for ultra high-speed video (including 1.5-Gbps uncompressed HDTV) delivery with a very short response time within one video frame.

A Basic Study on High Bandwidth Streaming in Realtime over Multipath Using LDPC-IRA Codes

This paper describes a distributed video streaming system using widely disparsed storages, in which each storage hosts send chunked video packets to single receiver through multipath network. By adding parity packets by forward error correction (FEC) along with source video data in each storage hosts, this system enables realtime video streamings even if there are unbalance between those hosts. In this paper, we introduce a model of this unbalance and its effect to the amount of needed packet sending, then discuss how to design redundancy rate in FEC. The result are shown to have a trade off among the range of balancing and the additional amount of sending packet needed for stable video streaming.